1. Field of the Invention
This invention relates to a method and apparatus for restoring cores, and more particularly, cores utilized for accommodating a roll of paper.
2. Description of the Prior Art
Newsprint and other paper used for printing is generally shipped from the paper mill in large rolls. When the rolls are made up at the paper mill, they are wound on a tubular core. Typically the cores are made of liner board and are usually provided with metal caps of the type described in U.S. Pat. No. 5,271,258, issued Dec. 21, 1993 to Bernier et al.
In the press room or other printing plant, the roll is mounted on an unwind apparatus with the core of the roll journaled on mandrels. Once the web of paper has been unwound from the core, the core is generally discarded or returned to a paper mill to be recycled as waste fiber. The core caps are first removed and restored for further use or sold for scrap.
The paper rolls are wound and unwound at high speeds and are, therefore, susceptible to misalignment while being wound, resulting in improper registry on the printing press, requiring constant alignment correction. A slight inconsistency in the outer diameter of 0.25 inches will cause the paper web, when being wound, to move away from the end of the core that includes the portion with the larger diameter. It is important, therefore, that the outer diameter be constant and retain its circular cylindrical configuration. Likewise, the inner diameter must not vary so that the axis of rotation is at the true center of the core and thus the roll of paper. Any out-of-center rotation will cause similar winding and unwinding problems.
Thus, it has not been contemplated to reuse a winding core once it has been utilized once other than to cut the core down to a smaller size. It has been found that after a single use, the winding core has been somewhat damaged. Even though such damage may appear negligible, the distortions in the outer diameter or center of rotation are usually unacceptable. Thus, the practice in industry is to discard the winding cores once a roll of paper web has been unwound therefrom. The discarded single use winding core is then returned to the paper mill as scrap liner board to be recycled as paper fiber.